Must read books for skeptics

After seeing losts of recommended book lists on Amazon, as well as being asked for book recommendations in person, I decided to put together a recommended reading list of my own. If you think I missed something important, I'll add it, but be aware I was intentionally being selective, picking only the very best books I know of. That said, there are gaps in it. I wouldn't mind adding a book on morality secular ethics, provided its of the same quality as the other six books on the list.